Multi-rake receiver

ABSTRACT

A wireless receiver includes M antennas that each receive a wireless signal. N rake receiver modules receive the wireless signals from the M antennas and combine multipath components of the wireless signals. A summing module receives outputs of the N rake receiver modules and combines the outputs to generate an output signal. M and N are integers greater than 1.

This application claims the benefit of U.S. Provisional Application No.60/825,356, filed on Sep. 12, 2006. The disclosure of the aboveapplication is incorporated herein by reference in its entirety.

FIELD

The present disclosure relates to wireless receivers, and moreparticularly to a wireless receiver that includes multiple rakereceivers.

BACKGROUND

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

In wireless communications, a transmitted signal (e.g. radio signals)may be received at a wireless receiver via multiple transmission paths.In other words, the wireless receiver includes an antenna that mayreceive the same transmitted signal via multiple paths. This tendency toreceive the same signal via multiple paths is referred to as“multipath.”

Multipath may cause reception errors and decrease quality in wirelesscommunications. For example, multipath may cause intersymbolinterference (ISI). A signal received via one of the paths may be out ofphase with the same signal received via another one of the paths.Signals that are received in phase with each other result in a strongersignal at the wireless receiver. Conversely, out of phase signals resultin a weak or fading signal at the wireless receiver (i.e. result inmultipath fading).

Referring now to FIG. 1, a wireless receiver 10 may include a rakereceiver 12 to compensate for the effects of multipath fading. A radiofrequency (RF) front end module 14 receives a wireless signal 16 from anantenna 18. The rake receiver 12 receives the wireless signal 16 fromthe front end module 14. The rake receiver 12 decodes each individualpath independently and combines the strongest transmissioncharacteristics of each of the paths to generate an output signal 20.

The wireless receiver 10 includes a frequency phase loop module 22 and atiming loop module 24. The frequency phase loop module 22 estimates afrequency offset based on the output signal 20. The timing loop module24 determines a sampling frequency difference between a wirelesstransmitter (not shown) and the wireless receiver 10.

Referring now to FIG. 2, the rake receiver 12 includes a plurality offingers 30-1, 30-2, 30-3, . . . , and 30-N (referred to collectively asfingers 30) and a plurality of corresponding delay modules 32-1, 32-2,32-3, . . . , and 32-N (referred to collectively as delay modules 32).The fingers 30 receive multipath signals 34 via a correspondingtransmission path. Each of the fingers 30 despreads a corresponding oneof the multipath signals 34. The delay modules 32 adjust time offsets ofthe multipath signals 34. A combining module 36 combines the adjustedmultipath signals 34 and generates an output signal 38. The combinedoutput signal 38 may have a higher signal-to-noise ratio than any of theindividual multipath signals 34.

SUMMARY

A wireless receiver includes M antennas that each receive a wirelesssignal. N rake receiver modules receive the wireless signals from the Mantennas, and combine multipath components of the wireless signals. Asumming module receives outputs of the N rake receiver modules andcombines the outputs to generate an output signal. M and N are integersgreater than 1.

In other features, each of the N rake receiver modules includes a rakeadaptation module that determines rake combining coefficients of acorresponding one of the N rake receiver modules. Each of the N rakereceiver modules includes a rake enable module that selectively enablesand disables fingers of a corresponding one of the N rake receivermodules based on signal strengths of the fingers. A rake select modulereceives the wireless signals, that compares signal strengths of thewireless signals to a threshold, and outputs a rake select signal basedon the comparison. The rake enable modules selectively enable anddisable respective ones of the N rake receiver modules based on the rakeselect signal.

In other features, a frequency phase loop module determines a frequencyoffset based on the output signal. A timing loop module that determinesa sampling frequency difference between the wireless receiver and atransmitter that transmits the wireless signals. The timing loop moduleincludes N error generation modules that each generate a timing errorbased on a corresponding one of the wireless signals, a summing modulethat combines the timing errors to generate a timing error signal, atiming loop that generates a timing correction signal based on thetiming error signal, and a sample timing control module that adjustssampling of the wireless signals based on the timing correction signal.

In other features, N receiver enable modules selectively enable anddisable receiver paths of the wireless receiver corresponding torespective ones of the wireless signals. The N receiver enable modulesenable M receiver paths and disable N−M receiver paths when M<N. The Nreceiver enable modules selectively enable and disable the receiverpaths based on a receiver select signal. A receiver select moduledetermines a number of the M antennas and generates the receiver selectsignal based on the number. The receiver select module generates anadjustment signal based on the number. M=N. An adaptive gain controlmodule adjusts a gain of the wireless receiver based on the wirelesssignals.

A wireless receiver includes M antenna means, each for receiving awireless signal, N rake receiver means for receiving the wirelesssignals from the M antenna means, and for combining multipath componentsof the wireless signals, and summing means for receiving outputs of theN rake receiver means and combining the outputs to generate an outputsignal. M and N are integers greater than 1.

In other features, each of the N rake receiver means includes rakeadaptation means for determining rake combining coefficients of acorresponding one of the N rake receiver means. Each of the N rakereceiver means includes rake enable means for selectively enabling anddisabling fingers of a corresponding one of the N rake receiver meansbased on signal strengths of the fingers. The wireless receiver furtherincludes rake select means for receiving the wireless signals, forcomparing signal strengths of the wireless signals to a threshold, andfor outputting a rake select signal based on the comparison. The rakeenable means selectively enable and disable respective ones of the Nrake receiver means based on the rake select signal.

In other features, the wireless receiver further includes frequencyphase loop means for determining a frequency offset based on the outputsignal. The wireless receiver further includes timing loop means fordetermining a sampling frequency difference between the wirelessreceiver and a transmitter that transmits the wireless signals. Thetiming loop means includes N error generation means, each for generatinga timing error based on a corresponding one of the wireless signals,summing means for combining the timing errors to generate a timing errorsignal, timing loop means for generating a timing correction signalbased on the timing error signal, and sample timing control means foradjusting sampling of the wireless signals based on the timingcorrection signal.

In other features, the wireless receiver further includes N receiverenable means for selectively enabling and disabling receiver paths ofthe wireless receiver corresponding to respective ones of the wirelesssignals. The N receiver enable means enable M receiver paths and disableN−M receiver paths when M<N. The N receiver enable means selectivelyenable and disable the receiver paths based on a receiver select signal.The wireless receiver further includes receiver select means fordetermining a number of the M antenna means and for generating thereceiver select signal based on the number. The receiver select meansgenerates an adjustment signal based on the number. M=N. The wirelessreceiver further includes an adaptive gain control means for adjusting again of the wireless receiver based on the wireless signals.

A method for operating a wireless receiver includes receiving a wirelesssignal at each of M antennas, receiving the wireless signals from the Mantennas at each of N rake receiver modules, combining multipathcomponents of the wireless signals at the N rake receiver modules, andreceiving outputs of the N rake receiver modules and combining theoutputs to generate an output signal at a summing module. M and N areintegers greater than 1.

In other features, the method further includes determining rakecombining coefficients of a corresponding one of the N rake receivermodules. The method further includes selectively enabling and disablingfingers of a corresponding one of the N rake receiver modules based onsignal strengths of the fingers. The method further includes comparingsignal strengths of the wireless signals to a threshold and outputting arake select signal based on the comparison. The method further includesselectively enabling and disabling respective ones of the N rakereceiver modules based on the rake select signal.

In other features, the method further includes determining a frequencyoffset based on the output signal. The method further includesdetermining a sampling frequency difference between the wirelessreceiver and a transmitter that transmits the wireless signals. Themethod further includes generating timing errors based on correspondingones of the wireless signals, combining the timing errors to generate atiming error signal, generating a timing correction signal based on thetiming error signal, and adjusting sampling of the wireless signalsbased on the timing correction signal.

In other features, the method further includes selectively enabling anddisabling receiver paths of the wireless receiver corresponding torespective ones of the wireless signals. The method further includesenabling M receiver paths and disabling N−M receiver paths when M<N. Themethod further includes selectively enabling and disabling the receiverpaths based on a receiver select signal. The method further includesdetermining a number of the M antennas and generating the receiverselect signal based on the number. The method further includesgenerating an adjustment signal based on the number. M=N. The methodfurther includes adjusting a gain of the wireless receiver based on thewireless signals.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the disclosure, are intended forpurposes of illustration only and are not intended to limit the scope ofthe disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a functional block diagram of a wireless receiver thatincludes a rake receiver according to the prior art;

FIG. 2 is a functional block diagram of a rake receiver according to theprior art;

FIG. 3 is a functional block diagram of a wireless receiver thatincludes multiple rake receiver modules according to the presentdisclosure;

FIG. 4 is a functional block diagram of rake receiver module accordingto the present disclosure;

FIG. 5 is a functional block diagram of a front end portion of awireless receiver according to the present disclosure;

FIG. 6 is a functional block diagram of a timing loop module accordingto the present disclosure;

FIG. 7 illustrates of a method of operating a wireless receiveraccording to the present disclosure;

FIG. 8A is a functional block diagram of a hard disk drive;

FIG. 8B is a functional block diagram of a DVD drive;

FIG. 8C is a functional block diagram of a high definition television;

FIG. 8D is a functional block diagram of a vehicle control system;

FIG. 8E is a functional block diagram of a cellular phone;

FIG. 8F is a functional block diagram of a set top box; and

FIG. 8G is a functional block diagram of a mobile device.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is in no wayintended to limit the disclosure, its application, or uses. For purposesof clarity, the same reference numbers will be used in the drawings toidentify similar elements. As used herein, the phrase at least one of A,B, and C should be construed to mean a logical (A or B or C), using anon-exclusive logical or. It should be understood that steps within amethod may be executed in different order without altering theprinciples of the present disclosure.

As used herein, the term module refers to an Application SpecificIntegrated Circuit (ASIC), an electronic circuit, a processor (shared,dedicated, or group) and memory that execute one or more software orfirmware programs, a combinational logic circuit, and/or other suitablecomponents that provide the described functionality.

Typically, a wireless receiver that communicates via a particularcommunication protocol (for example only, IEEE standard 802.11a,802.11b, and/or 802.11g) includes a single receive antenna and acorresponding rake receiver that receives transmitted wireless signals.A wireless receiver according to the present disclosure includesmultiple receive antennas and corresponding rake receivers that eachreceive multipath components of a transmitted wireless signal. Thewireless receiver spatially combines signals from each of the rakereceivers to increase gain and extend a reception range of the wirelessreceiver.

Referring now to FIG. 3, a wireless receiver 100 includes receiveantennas 102-1, 102-2, 102-3, . . . , and 102-M (referred tocollectively as multiple receive antennas 102) and corresponding frontend modules 104-1, 104-2, 104-3, . . . , and 104-M (referred tocollectively as front end modules 104). The antennas 102 and the frontend modules 104 receive and process wireless signals 106-1, 106-2,106-3, . . . , and 106-M (referred to collectively as wireless signals106). Rake receiver modules 108-1, 108-2, 108-3, . . . , and 108-M(referred to collectively as rake receiver modules 108) each receivecorresponding wireless signals 106 from the antennas 102 via therespective front end modules 104.

Each of the rake receiver modules 108 decodes and combinescharacteristics of one of the corresponding wireless signals 106 togenerate rake receiver output signals 110-1, 110-2, 110-3, . . . , and110-M (referred to collectively as output signals 110). The outputsignals 110 are combined together to generate an output signal 112. Forexample, the wireless receiver 100 spatially combines the output signals110 at a summing module 114 to generate the output signal 112. Theoutput signal 112 is output to a demodulator 116 and a descrambler 118.

The wireless receiver 100 includes a frequency phase loop module 120 anda timing loop module 122. The frequency loop module 120 estimates afrequency offset 124 based on the output signal 112 and compensates eachof the wireless signals 106 accordingly. For example, frequencycorrection multipliers 126-1, 126-2, 126-3, . . . , and 126-M (referredto collectively as frequency correction multipliers 126) receive andmultiply the frequency offset 124 and respective ones of the wirelesssignals 106. The timing loop module 122 receives the wireless signals106 and determines a sampling frequency difference between a wirelesstransmitter (not shown) and the wireless receiver 100.

Referring now to FIG. 4, an intermediate portion 200 of the wirelessreceiver 100 is shown in more detail. Each of the rake receiver modules108 communicates with a corresponding one of Barker correlators 202-1,202-2, 202-3, . . . , and 202-M (referred to collectively as Barkercorrelators 202). Each of the Barker correlators 202 communicates with arespective one of the frequency correction multipliers 126 to decode thewireless signals 106.

Each of the rake receiver modules 108 includes a rake receiver 204, arake adaptation module 206, and a rake enable module 208 as illustratedwith respect to the rake receiver module 108-1. The rake receiver 204receives a downsampled wireless signal 210 from a downsampler 212. Thedownsampler 212 reduces a sampling rate of a corresponding one of thewireless signals 106 by an integer factor (for example only, by a factorof 2). In the present implementation, the downsampler 212 reduces thesampling rate from 22 MHz to 11 MHz.

The rake adaptation module 206 determines rake combining coefficients ofthe rake receiver 204 based on the output signal 112 and the downsampledwireless signal 210. For example, the rake receiver 204 includes aplurality of the fingers 30 (as described above with respect to FIG. 2).The rake receiver 204 delays and combines the various multipath signalsof each of the fingers 30 based on the rake combining coefficients. Therake adaptation module 206 adjusts the rake combining coefficientsaccording to changes in the multipath signals.

The rake enable module 208 selectively enables and disables the fingers30 of the rake receiver 204 based on a rake select signal 214. Forexample, the wireless receiver 100 includes multiple rake receivermodules 108. Consequently, the wireless receiver 100 receives andcombines an increased number of the fingers 30. Each of the fingers 30contributes noise. In particular, weaker ones of the fingers 30 tend tocontribute a greater level of noise. The rake enable module 208selectively disables the weaker ones of the fingers 30 to reduce noise.

The rake enable module 208 receives the rake select signal 214 from arake select module 216. The rake select module 216 receives the wirelesssignal 106 and generates the rake select signal 214 accordingly. Forexample, the rake select module 216 may determine respective signalstrengths of each of the fingers 30 of the wireless signal 106 andcompare the signal strengths to a threshold. The rake select signal 214indicates which of the fingers 30 have a signal strength that is greaterthan the threshold. The rake enable module 208 disables the fingers 30that do not have a signal strength greater than the threshold.

The wireless receiver includes a bit synchronizing (bitsync) module 220.The bitsync module 220 receives the wireless signal 106 and determinessampling boundaries for a desired downsampling frequency. For example,the wireless receiver 100 may reduce the sampling rate from 22 MHz to 1MHz. The downsampler 212 reduces the sampling rate from 22 MHz to 11MHz. A downsampler 222 reduces the sampling rate from 11 MHz to 1 MHz.The bitsync module 220 determines the sampling boundaries based onoutputs of the Barker correlators 202. For example, the bitsync module220 determines the sampling boundaries based on a maximum magnitude ofthe outputs of the Barker correlators 202 (i.e. a maximum output of allof the Barker correlators 202).

Referring now to FIG. 5, a front end portion 300 of the wirelessreceiver 100 is shown in more detail. Each of the front end modules 104includes an analog-to-digital converter (ADC) 302, a filter module 304,a downsampler 306, and a receiver enable module 308 as shown withrespect to the front end module 104-1. The ADC 302 converts the receivedwireless signal 106-1 from an analog signal to a digital signal. The ADC302 samples the wireless signal 106-1 based on feedback from the timingloop module 122. The filter module 304 filters the signal 106-1according to a particular wireless communication protocol. For exampleonly, the filter module 304 may include an IEEE standard 802.11b filter.

The receiver enable module 308 selectively enables and disables thereceiver path corresponding to the signal 106-1. For example only, whenthe receiver 100 includes only 2 antennas (e.g. the antennas thatreceive the signals 106-1 and 106-2), additional receiver paths (e.g.the receiver paths corresponding to signals 106-3 through 106-M) may beunnecessary. The receiver enable module 308 disables any unnecessaryreceiver paths (e.g. forces the signal values of the receiver paths tozero).

The receiver enable module 308 operates according to a receiver selectsignal 310. The receiver enable module 308 receives the receiver selectsignal 310 from a receiver select module 312. The receiver select module312 determines which receiver paths to enable and disable. For exampleonly, the receiver select module 312 may automatically detect a numberof antennas that are present and enable/disable receiver pathsaccordingly. In another implementation, a user and/or manufacturercalibrates the receiver select module 312 based on a known number ofantennas.

The receiver select module 312 may generate one or more adjustmentsignals 314 based on the number of antennas and corresponding enabledreceiver paths. The receiver select module 312 outputs the adjustmentsignals 314 to components of the receiver 100 that are sensitive to thenumber of enabled receiver paths. For example only, bandwidths of thefrequency phase loop module 120 and the timing loop module 122 may varybased on the number of enabled receiver paths. Coefficients of the rakeadaptation modules 108 may vary based on the number of enabled receiverpaths.

The receiver 100 may include an adaptive gain control (AGC) module 316.The AGC module 316 adjusts gain of the receiver 100 based on thewireless signals 106.

Referring now to FIG. 6, the timing loop module 122 is shown in moredetail. The timing loop module 122 includes zero-crossing errorgeneration modules 400-1, 400-2, 400-3, . . . , and 400-M (referred tocollectively as zero-crossing error generation modules 400), a timingloop 402, and a sample timing control module 404. Each of thezero-crossing error generation modules 400 receives a corresponding oneof the wireless signals 106. The zero-crossing error generation modules400 generate respective timing errors 406-1, 406-2, 406-3, . . . , and406-M (referred to collectively as timing errors 406) based on thewireless signals 106.

A summing module 408 receives and combines the timing errors 406 andgenerates a timing error signal 410. The timing loop 402 receives thetiming error signal 410 and generates a timing correction signal 412based on the timing error signal 410. The sample timing control module404 adjusts sample timing of the ADCs 302 of each of the front endmodules 104 based on the timing correction signal 412.

Referring now to FIG. 7, a method 500 for operating a wireless receiver100 having multiple receiver paths begins in step 502. In step 504, thereceiver select module 312 determines a number M of the antennas 102present in the wireless receiver 100. In step 506, the receiver selectmodule 312 enables M of the antennas 102. In step 508, the receiver 100receives wireless signals 106 via the M antennas 102. In step 510, Mrake receiver modules 108 receive the wireless signals 106. In step 512,outputs of the M rake receiver modules 108 are spatially combined toincrease the gain of the wireless receiver 100. The method 500 ends instep 514.

Referring now to FIGS. 8A-8G, various exemplary implementationsincorporating the teachings of the present disclosure are shown.

Referring now to FIG. 8A, the teachings of the disclosure can beimplemented in an I/O interface 615 of a hard disk drive (HDD) 600. Forexample, the I/O interface 615 may include a wireless receiver forreceiving data. The HDD 600 includes a hard disk assembly (HDA) 601 anda HDD printed circuit board (PCB) 602. The HDA 601 may include amagnetic medium 603, such as one or more platters that store data, and aread/write device 604. The read/write device 604 may be arranged on anactuator arm 605 and may read and write data on the magnetic medium 603.Additionally, the HDA 601 includes a spindle motor 606 that rotates themagnetic medium 603 and a voice-coil motor (VCM) 607 that actuates theactuator arm 605. A preamplifier device 608 amplifies signals generatedby the read/write device 604 during read operations and provides signalsto the read/write device 604 during write operations.

The HDD PCB 602 includes a read/write channel module (hereinafter, “readchannel”) 609, a hard disk controller (HDC) module 610, a buffer 611,nonvolatile memory 612, a processor 613, and a spindle/VCM driver module614. The read channel 609 processes data received from and transmittedto the preamplifier device 608. The HDC module 610 controls componentsof the HDA 601 and communicates with an external device (not shown) viathe I/O interface 615. The external device may include a computer, amultimedia device, a mobile computing device, etc. The I/O interface 615may include wireline and/or wireless communication links.

The HDC module 610 may receive data from the HDA 601, the read channel609, the buffer 611, nonvolatile memory 612, the processor 613, thespindle/VCM driver module 614, and/or the I/O interface 615. Theprocessor 613 may process the data, including encoding, decoding,filtering, and/or formatting. The processed data may be output to theHDA 601, the read channel 609, the buffer 611, nonvolatile memory 612,the processor 613, the spindle/VCM driver module 614, and/or the I/Ointerface 615.

The HDC module 610 may use the buffer 611 and/or nonvolatile memory 612to store data related to the control and operation of the HDD 600. Thebuffer 611 may include DRAM, SDRAM, etc. The nonvolatile memory 612 mayinclude flash memory (including NAND and NOR flash memory), phase changememory, magnetic RAM, or multi-state memory, in which each memory cellhas more than two states. The spindle/VCM driver module 614 controls thespindle motor 606 and the VCM 607. The HDD PCB 602 includes a powersupply 616 that provides power to the components of the HDD 600.

Referring now to FIG. 8B, the teachings of the disclosure can beimplemented in an I/O interface 629 of a DVD drive 618 or of a CD drive(not shown). For example, the I/O interface 629 may include a wirelessreceiver for receiving data. The DVD drive 618 includes a DVD PCB 619and a DVD assembly (DVDA) 620. The DVD PCB 619 includes a DVD controlmodule 621, a buffer 622, nonvolatile memory 623, a processor 624, aspindle/FM (feed motor) driver module 625, an analog front-end module626, a write strategy module 627, and a DSP module 628.

The DVD control module 621 controls components of the DVDA 620 andcommunicates with an external device (not shown) via the I/O interface629. The external device may include a computer, a multimedia device, amobile computing device, etc. The I/O interface 629 may include wirelineand/or wireless communication links.

The DVD control module 621 may receive data from the buffer 622,nonvolatile memory 623, the processor 624, the spindle/FM driver module625, the analog front-end module 626, the write strategy module 627, theDSP module 628, and/or the I/O interface 629. The processor 624 mayprocess the data, including encoding, decoding, filtering, and/orformatting. The DSP module 628 performs signal processing, such as videoand/or audio coding/decoding. The processed data may be output to thebuffer 622, nonvolatile memory 623, the processor 624, the spindle/FMdriver module 625, the analog front-end module 626, the write strategymodule 627, the DSP module 628, and/or the I/O interface 629.

The DVD control module 621 may use the buffer 622 and/or nonvolatilememory 623 to store data related to the control and operation of the DVDdrive 618. The buffer 622 may include DRAM, SDRAM, etc. The nonvolatilememory 623 may include flash memory (including NAND and NOR flashmemory), phase change memory, magnetic RAM, or multi-state memory, inwhich each memory cell has more than two states. The DVD PCB 619includes a power supply 630 that provides power to the components of theDVD drive 618.

The DVDA 620 may include a preamplifier device 631, a laser driver 632,and an optical device 633, which may be an optical read/write (ORW)device or an optical read-only (OR) device. A spindle motor 634 rotatesan optical storage medium 635, and a feed motor 636 actuates the opticaldevice 633 relative to the optical storage medium 635.

When reading data from the optical storage medium 635, the laser driverprovides a read power to the optical device 633. The optical device 633detects data from the optical storage medium 635, and transmits the datato the preamplifier device 631. The analog front-end module 626 receivesdata from the preamplifier device 631 and performs such functions asfiltering and A/D conversion. To write to the optical storage medium635, the write strategy module 627 transmits power level and timing datato the laser driver 632. The laser driver 632 controls the opticaldevice 633 to write data to the optical storage medium 635.

Referring now to FIG. 8C, the teachings of the disclosure can beimplemented in a network interface 643 of a high definition television(HDTV) 637. The HDTV 637 includes a HDTV control module 638, a display639, a power supply 640, memory 641, a storage device 642, the networkinterface 643, and an external interface 645. If the network interface643 includes a wireless local area network interface, an antenna (notshown) may be included.

The HDTV 637 can receive input signals from the network interface 643and/or the external interface 645, which can send and receive data viacable, broadband Internet, and/or satellite. The HDTV control module 638may process the input signals, including encoding, decoding, filtering,and/or formatting, and generate output signals. The output signals maybe communicated to one or more of the display 639, memory 641, thestorage device 642, the network interface 643, and the externalinterface 645.

Memory 641 may include random access memory (RAM) and/or nonvolatilememory such as flash memory, phase change memory, or multi-state memory,in which each memory cell has more than two states. The storage device642 may include an optical storage drive, such as a DVD drive, and/or ahard disk drive (HDD). The HDTV control module 638 communicatesexternally via the network interface 643 and/or the external interface645. The power supply 640 provides power to the components of the HDTV637.

Referring now to FIG. 8D, the teachings of the disclosure may beimplemented in a network interface 652 of a vehicle 646. The vehicle 646may include a vehicle control system 647, a power supply 648, memory649, a storage device 650, and the network interface 652. If the networkinterface 652 includes a wireless local area network interface, anantenna (not shown) may be included. The vehicle control system 647 maybe a powertrain control system, a body control system, an entertainmentcontrol system, an anti-lock braking system (ABS), a navigation system,a telematics system, a lane departure system, an adaptive cruise controlsystem, etc.

The vehicle control system 647 may communicate with one or more sensors654 and generate one or more output signals 656. The sensors 654 mayinclude temperature sensors, acceleration sensors, pressure sensors,rotational sensors, airflow sensors, etc. The output signals 656 maycontrol engine operating parameters, transmission operating parameters,suspension parameters, etc.

The power supply 648 provides power to the components of the vehicle646. The vehicle control system 647 may store data in memory 649 and/orthe storage device 650. Memory 649 may include random access memory(RAM) and/or nonvolatile memory such as flash memory, phase changememory, or multi-state memory, in which each memory cell has more thantwo states. The storage device 650 may include an optical storage drive,such as a DVD drive, and/or a hard disk drive (HDD). The vehicle controlsystem 647 may communicate externally using the network interface 652.

Referring now to FIG. 8E, the teachings of the disclosure can beimplemented in a cellular phone network interface 667 and/or a networkinterface 668 of a cellular phone 658. The cellular phone 658 includes aphone control module 660, a power supply 662, memory 664, a storagedevice 666, and the cellular network interface 667. The cellular phone658 may include the network interface 668, a microphone 670, an audiooutput 672 such as a speaker and/or output jack, a display 674, and auser input device 676 such as a keypad and/or pointing device. If thenetwork interface 668 includes a wireless local area network interface,an antenna (not shown) may be included.

The phone control module 660 may receive input signals from the cellularnetwork interface 667, the network interface 668, the microphone 670,and/or the user input device 676. The phone control module 660 mayprocess signals, including encoding, decoding, filtering, and/orformatting, and generate output signals. The output signals may becommunicated to one or more of memory 664, the storage device 666, thecellular network interface 667, the network interface 668, and the audiooutput 672.

Memory 664 may include random access memory (RAM) and/or nonvolatilememory such as flash memory, phase change memory, or multi-state memory,in which each memory cell has more than two states. The storage device666 may include an optical storage drive, such as a DVD drive, and/or ahard disk drive (HDD). The power supply 662 provides power to thecomponents of the cellular phone 658.

Referring now to FIG. 8F, the teachings of the disclosure can beimplemented in a network interface 685 of a set top box 678. The set topbox 678 includes a set top control module 680, a display 681, a powersupply 682, memory 683, a storage device 684, and the network interface685. If the network interface 685 includes a wireless local area networkinterface, an antenna (not shown) may be included.

The set top control module 680 may receive input signals from thenetwork interface 685 and an external interface 687, which can send andreceive data via cable, broadband Internet, and/or satellite. The settop control module 680 may process signals, including encoding,decoding, filtering, and/or formatting, and generate output signals. Theoutput signals may include audio and/or video signals in standard and/orhigh definition formats. The output signals may be communicated to thenetwork interface 685 and/or to the display 681. The display 681 mayinclude a television, a projector, and/or a monitor.

The power supply 682 provides power to the components of the set top box678. Memory 683 may include random access memory (RAM) and/ornonvolatile memory such as flash memory, phase change memory, ormulti-state memory, in which each memory cell has more than two states.The storage device 684 may include an optical storage drive, such as aDVD drive, and/or a hard disk drive (HDD).

Referring now to FIG. 8G, the teachings of the disclosure can beimplemented in a network interface 694 of a mobile device 689. Themobile device 689 may include a mobile device control module 690, apower supply 691, memory 692, a storage device 693, the networkinterface 694, and an external interface 699. If the network interface694 includes a wireless local area network interface, an antenna (notshown) may be included.

The mobile device control module 690 may receive input signals from thenetwork interface 694 and/or the external interface 699. The externalinterface 699 may include USB, infrared, and/or Ethernet. The inputsignals may include compressed audio and/or video, and may be compliantwith the MP3 format. Additionally, the mobile device control module 690may receive input from a user input 696 such as a keypad, touchpad, orindividual buttons. The mobile device control module 690 may processinput signals, including encoding, decoding, filtering, and/orformatting, and generate output signals.

The mobile device control module 690 may output audio signals to anaudio output 697 and video signals to a display 698. The audio output697 may include a speaker and/or an output jack. The display 698 maypresent a graphical user interface, which may include menus, icons, etc.The power supply 691 provides power to the components of the mobiledevice 689. Memory 692 may include random access memory (RAM) and/ornonvolatile memory such as flash memory, phase change memory, ormulti-state memory, in which each memory cell has more than two states.The storage device 693 may include an optical storage drive, such as aDVD drive, and/or a hard disk drive (HDD). The mobile device may includea personal digital assistant, a media player, a laptop computer, agaming console, or other mobile computing device.

Those skilled in the art can now appreciate from the foregoingdescription that the broad teachings of the disclosure can beimplemented in a variety of forms. Therefore, while this disclosureincludes particular examples, the true scope of the disclosure shouldnot be so limited since other modifications will become apparent to theskilled practitioner upon a study of the drawings, the specification,and the following claims.

What is claimed is:
 1. A wireless receiver comprising: M antennasconfigured to each receive a wireless signal; front end modulesconfigured to each receive a respective one of the wireless signals; Nrake receiver modules configured to receive the wireless signals fromthe M antennas, wherein the N rake receiver modules are configured tocombine multipath components of the wireless signals; a summing moduleconfigured to receive outputs of the N rake receiver modules, whereinthe summing module is configured to sum the outputs to generate anoutput signal; and a receiver select module configured to detect (i) anumber of the M antennas or (ii) a number of enabled receiver paths andto generate a receiver select signal based on (i) the number of the Mantennas or (ii) the number of the enabled receiver paths, wherein: Mand N are integers greater than 1; each of the front end modulescomprises a receiver enable module; the receiver enable modules areconfigured to receive the receiver select signal; and the receiverselect module is configured to control the receiver enable modules toselectively disable an unnecessary receiver path based on the receiverselect signal.
 2. The wireless receiver of claim 1, wherein: each of theN rake receiver modules includes a rake adaptation module; and each ofthe rake adaptation modules is configured to determine rake combiningcoefficients of a corresponding one of the N rake receiver modules. 3.The wireless receiver of claim 1, wherein: each of the N rake receivermodules includes a rake enable module; and each of the rake enablemodules is configured to selectively enable and disable fingers of acorresponding one of the N rake receiver modules based on signalstrengths of the fingers.
 4. The wireless receiver of claim 3, furthercomprising a rake select module configured to receive the wirelesssignals, compare signal strengths of the wireless signals to athreshold, and output a rake select signal based on the comparison. 5.The wireless receiver of claim 4, wherein the rake enable modules areconfigured to selectively enable and disable respective ones of the Nrake receiver modules based on the rake select signal.
 6. The wirelessreceiver of claim 1, further comprising a frequency phase loop moduleconfigured to determine a frequency offset based on the output signal.7. The wireless receiver of claim 1, further comprising a timing loopmodule configured to determine a sampling frequency difference betweenthe wireless receiver and a transmitter, wherein the transmitter isconfigured to transmit the wireless signals.
 8. The wireless receiver ofclaim 7, wherein the timing loop module includes: N error generationmodules configured to each generate a timing error based on acorresponding one of the wireless signals; a summing module configuredto combine the timing errors to generate a timing error signal; a timingloop configured to generate a timing correction signal based on thetiming error signal; and a sample timing control module configured toadjust sampling of the wireless signals based on the timing correctionsignal.
 9. The wireless receiver of claim 1, wherein: the wirelessreceiver comprises N of the receiver enable modules; and the N receiverenable modules are configured to enable M receiver paths and disable N−Mreceiver paths when M<N.
 10. The wireless receiver of claim 1, whereinthe receiver select module is configured to generate an adjustmentsignal based on the number.
 11. The wireless receiver of claim 1,wherein M=N.
 12. The wireless receiver of claim 1, further comprising anadaptive gain control module configured to adjust a gain of the wirelessreceiver based on the wireless signals.
 13. The wireless receiver ofclaim 1, wherein the receiver enable modules are configured to forcesignal values of the unnecessary receiver path to zero when disablingthe unnecessary receiver path.
 14. The wireless receiver of claim 1,wherein: the receiver select module is configured to generate anadjustment signal based on the at least one of the number of the Mantennas or the number of the enabled receiver paths; and the adjustmentsignal is generated to disable the unnecessary receiver path.
 15. Thewireless receiver of claim 14, wherein the receiver select module isconfigured to output the adjustment signal to components, wherein thecomponents are sensitive to a number of enabled receiver paths.
 16. Thewireless receiver of claim 14, further comprising at least one of afrequency phase loop module and a timing loop module, wherein bandwidthof the at least one of a frequency phase loop module and a timing loopmodule is adjusted based on the adjustment signal.
 17. The wirelessreceiver of claim 14, wherein bandwidth of the N rake receiver modulesis adjusted based on the adjustment signal.
 18. The wireless receiver ofclaim 1, wherein the receiver select module is configured to: detect thenumber of the M antennas and the number of the enabled receiver paths;and generate the receiver select signal based on the number of the Mantennas and the number of the enabled receiver paths.
 19. The wirelessreceiver of claim 1, further comprising a downsampler configured todownsample the wireless signals to generate a downsampled wirelesssignal, wherein: each of the N rake receiver modules includes a rakeadaptation module; and each of the rake adaptation modules is configuredto determine rake combining coefficients of a corresponding one of the Nrake receiver modules based on the output signal and the downsampledwireless signal.
 20. The wireless receiver of claim 1, furthercomprising a rake select module configured to: receive the wirelesssignal; determine signal strengths of each finger of the wirelesssignal; compare the signal strengths to a threshold; and indicate afinger with a signal strength that is greater than the threshold,wherein the rake enable module is configured to disable fingers withsignal strengths less than the threshold.
 21. The wireless receiver ofclaim 1, further comprising a bit synchronizing module configured toreceive one of the wireless signals and determine sampling boundariesfor a downsampling frequency.
 22. The wireless receiver of claim 21,further comprising a downsampler configured to reduce a sampling rate ofthe one of the wireless signals based on the downsampling frequency. 23.The wireless receiver of claim 21, further comprising a downsamplerconfigured to reduce a sampling rate of the output signal of the summingmodule based on the downsampling frequency.
 24. The wireless receiver ofclaim 16, wherein bandwidth of the frequency phase loop module isadjusted based on the at least one of the number of the M antennas orthe number of the enabled receiver paths.
 25. The wireless receiver ofclaim 1, wherein the unnecessary receiver path comprises one of the Mantennas, one of the front end modules, and one of the N rake receivermodules.
 26. A wireless receiver comprising: M antenna means, each forreceiving a wireless signal; front end means, each for receiving arespective one of the wireless signals; N rake receiver means forreceiving the wireless signals from the M antenna means, and forcombining multipath components of the wireless signals; summing meansfor receiving outputs of the N rake receiver means and summing theoutputs to generate an output signal; and a receiver select means fordetecting (i) a number of the M antenna means or (ii) a number ofenabled receiver paths and for generating a receiver select signal basedon (i) the number of the M antenna means or (ii) the number of enabledreceiver paths, wherein: M and N are integers greater than 1; each ofthe front end means comprising a receiver enable module; the receiverenable means receiving the receiver select signal; and the receiverselect means controlling the receiver enable means to selectivelydisable an unnecessary receiver path based on the receiver selectsignal.
 27. The wireless receiver of claim 26, wherein each of the Nrake receiver means includes rake adaptation means for determining rakecombining coefficients of a corresponding one of the N rake receivermeans.
 28. The wireless receiver of claim 26, wherein each of the N rakereceiver means includes rake enable means for selectively enabling anddisabling fingers of a corresponding one of the N rake receiver meansbased on signal strengths of the fingers.
 29. The wireless receiver ofclaim 28, further comprising rake select means for receiving thewireless signals, for comparing signal strengths of the wireless signalsto a threshold, and for outputting a rake select signal based on thecomparison.
 30. The wireless receiver of claim 29, wherein the rakeenable means selectively enable and disable respective ones of the Nrake receiver means based on the rake select signal.
 31. The wirelessreceiver of claim 26, further comprising frequency phase loop means fordetermining a frequency offset based on the output signal.
 32. Thewireless receiver of claim 26, further comprising timing loop means fordetermining a sampling frequency difference between the wirelessreceiver and a transmitter, wherein the transmitter transmits thewireless signals.
 33. The wireless receiver of claim 32, wherein thetiming loop means includes: N error generation means, each forgenerating a timing error based on a corresponding one of the wirelesssignals; summing means for combining the timing errors to generate atiming error signal; timing loop means for generating a timingcorrection signal based on the timing error signal; and sample timingcontrol means for adjusting sampling of the wireless signals based onthe timing correction signal.
 34. The wireless receiver of claim 26,wherein: the wireless receiver comprises N of the receiver enablemodules; and the N receiver enable means enable M receiver paths anddisable N−M receiver paths when M<N.
 35. The wireless receiver of claim26, wherein the receiver select means generates an adjustment signalbased on the number.
 36. The wireless receiver of claim 26, wherein M=N.37. The wireless receiver of claim 26, further comprising adaptive gaincontrol means for adjusting a gain of the wireless receiver based on thewireless signals.
 38. A method for operating a wireless receivercomprising: receiving a wireless signal at each of M antennas; receivinga respective one of the wireless signals at each of a plurality of frontend modules; receiving the wireless signals from the M antennas at eachof N rake receiver modules; combining multipath components of thewireless signals at the N rake receiver modules; receiving outputs ofthe N rake receiver modules and summing the outputs to generate anoutput signal at a summing module; detecting (i) a number of the Mantennas or (ii) a number of enabled receiver paths; and generating areceiver select signal based on (i) the number of the M antennas or (ii)the number of the enabled receiver paths, wherein: M and N are integersgreater than 1; receiving the receiver select signal at receiver enablemodules of the plurality of front end modules; and selectively disablingan unnecessary receiver path based on the receiver select signal. 39.The method of claim 38, further comprising determining rake combiningcoefficients of a corresponding one of the N rake receiver modules. 40.The method of claim 38, further comprising selectively enabling anddisabling fingers of a corresponding one of the N rake receiver modulesbased on signal strengths of the fingers.
 41. The method of claim 40,further comprising: comparing signal strengths of the wireless signalsto a threshold; and outputting a rake select signal based on thecomparison.
 42. The method of claim 41, further comprising selectivelyenabling and disabling respective ones of the N rake receiver modulesbased on the rake select signal.
 43. The method of claim 38, furthercomprising determining a frequency offset based on the output signal.44. The method of claim 38, further comprising determining a samplingfrequency difference between the wireless receiver and a transmitterthat transmits the wireless signals.
 45. The method of claim 44, furthercomprising: generating timing errors based on corresponding ones of thewireless signals; combining the timing errors to generate a timing errorsignal; generating a timing correction signal based on the timing errorsignal; and adjusting sampling of the wireless signals based on thetiming correction signal.
 46. The method of claim 38, furthercomprising: providing N of the receiver enable modules; and enabling Mreceiver paths and disabling N−M receiver paths when M<N.
 47. The methodof claim 38, further comprising generating an adjustment signal based onthe number.
 48. The method of claim 38, wherein M=N.
 49. The method ofclaim 38, further comprising adjusting a gain of the wireless receiverbased on the wireless signals.